1. Field of the Invention
The present invention generally relates to the field of modem telecommunication technologies and devices. More particularly, the present invention relates to the field of interfacing devices to be used with a telephone system terminal for transmitting information to a telephone provider's central office which is in turn connected to one or more public safety answering points (PSAPs).
2. Description of the Prior Art
In many cities and communities, public safety answering points (PSAPs) have been established to answer emergency phone calls. In an emergency situation, a caller from the emergency spot places an emergency phone call through the telephone system and the emergency phone call will be routed to a PSAP. Currently most telephone systems have the function of identifying the emergency telephone number to the PSAP so that the PSAP can locate the emergency spot and provide quick response.
In many business establishments such as a large company, hotels, department stores, etc., private branch exchange (PBX) systems are used which handle many extension telephone stations. This poses a problem for identifying the exact emergency location within such business establishment. With the current telephone systems, when an emergency phone call is placed from an extension station within a PBX system, the phone call can be routed to a PSAP.
However, since the phone call from the extension station passes through the PBX system first, the PSAP will only know the identification of the PBX system without knowing the particular extension stations. As a result, when the emergency personnel arrive at the business establishment, they are often at a loss as to where exactly the emergency location is and they have to search through many offices in the office building or many suites in the hotel or many floors in the department store.
Therefore, there is a need in the telephone network and emergency response network to provide further identification of the extension station within a PBX system from which an emergency phone call is made.
U.S. Pat. No. 5,347,568 issued to Moody et al. on Sep. 13, 1994 for "Emergency Call Station Identification System" discloses a device for identifying a specific station, among a plurality of geographically-dispersed stations represented by a common telephone number and serviced by a common PBX, which has initiated an emergency "9-1-1" telephone call. The device can identify the specific station which initiated the emergency "9-1-1" telephone call to the appropriate PSAP which is connected to an enhanced "9-1-1" emergency call network. The device has functions to convert the protocol of the PBX to the protocol of the emergency call network. It also assigns an arbitrary designation representing the specific station which initiated the emergency phone call.
In many emergency situations, simply identifying the extension station from which an emergency phone call is made is insufficient. For example, it is also desirable for the emergency crew to know where the extension station is located, directions to that particular location, etc.
In addition, it is also desirable for the on-site management personnel or the security staff to be alerted as well when an emergency phone call was made by one of the extension stations of the PBX system.
Therefore, it is highly desirable to provide an interfacing device to be used with a telephone system for translating extended station information to one or more PSAP.